Process of nitrating solvent naphtha.



nnrrsn STATES PATENT OFFICE.

GUSTAV SCHULTZ, OF MUNICH, GERMANY.

Specification of Letters Patent.

Patented Sept. 8, 1908.

Applicatidn filed October a, 1907. Serial No. 395,775.

To all whom it may concern:

Be it known that I, GUSTAV SCHULTZ, professor and doctor, subject of the King of Bavaria, residing at 3 Gisclastrasse, Munich,

Bavaria, Germany, have invented new and useful Improvements in Processes of Nitratng Solvent N apht'ha, of which the following 1s a specification.

It is well known that the so called solvent naphtha,heretofore used as a dissolving agent for various purposes, which is obtamed from coal-tar oil,after the removal therefrom of the acid and basic components by alternate treatment with alkalies and acids, and after the removal of the bodies contained in it which become resinous with sulfurlc acid, (such as styrole, cumaron, 1n'

tain also hydrocarbons having higher boiling points. 1

. The object of the present invention is to produce from solvent naphtha by nitration, mixtures of nitro-compound's' of the hydrocarbons contained in the said solvent naphtha, and es ecially from such as have a boiling point 0 about 120 degrees to 180 de ees centigrade, and which have been we washed with sulfuric acid; as it hasbeen found that these nitro-compounds'are es ecially well suited for the production of hig y effective safety explosives.

It may be stated that raw impure tar oil or raw solvent naphtha has already been nitrated. But the process heretofore employed has no technical value, because these raw oils are very easily attacked and destroyed by nitric acid, and easily resinate with sulfuric acid. In conse uence of this vulnerability there occur vio ent reactions on nitration with a mixture of nitric and sulfuric acids which destroy the greater art of the tar oils, so that only small yields 0 nitrocom ounds contaminated with various bypro ucts are obtained and which compounds are quite unsuitable for the production of safety explosives on account of their impurity.

In the tha em oyed as the raw material is by thoroug treatment with soda and sulfuric acid, first freed from thebasic products, acid oils, pyridin bases, and easily resinated bodies, which are valueless for the intended purpose; and is then purified by repeated distillation, and finally yields a liquid as clear as water, and the boiling point thereof lies between 120 degrees and 180 degrees C. and it has a specific gravity of about 0.860 to 0.875 at 15 degrees C. If such a solvent naphtha is nitrated in the manner to be hereinafter described, a product -is at last talline substances with oily liquids. While the solid crystalline bodies mainly consist of ethylbenzol, nitrated pseudocuniol and mesitylene, and also nitrated toluol, the abovementioned oily liquids are in all probability likewise highly nitrated products of those above mentioned compounds contained in characterized. a

It has been proved that both the solid and the oily nitro-products are suitable for the production of safety explosives, but that ac cording to whether the solid only, the olly are empl0yed,explosives of various s attering power are obtained and therefore'the mtrating process about to be describedls so conducted that according to the desired object, the solid only, the oily only or various mixtures of them are obtained, In order to eflfect this, the solvent naphtha is either nitrated as it is, or it is separated into two or three fractions, by fractional distillation, each of which fractions is subjected by itself to nitration. If the solvent naphtha is nitrated as it is, a mixture of so id and oily nitro-compounds is obtained. But 1f the solvent naphtha is separated by dlstlllation into, for example, three fractions, the first of which boils at 120 degrees to-140 degrees, the second at 140 degrees to 160 degrees, and the third at 160 degrees to 180 degrees cent grade, each of said fractions is nitrated by itself, the first yields exclusively solid nltro products; the second for the' greater part oily nitro products mixed with solid; and

the third for the greater part solid crystalpresent invention the solvent naph-' obtained which forms a mixture of solid cryshighly nitrated xylene, highly nitrated I the solvent naphtha which have not yetbeen only, or mixtures of the nitro-com ounds' line nitro products. These bodies are highly nitrated, products in the first case; with hydrocarbons of lowest boiling points such as xylol, and ethylbenzol, in the second case, with hydrocarbons of medium into three fractions, is decomposed into two only, for example, into one that boils at 120 degrees to 140 degrees and the other at 140 degrees to 180 degrees; or into one the boiling point of which lies at 120 degrees to 160 degrees and the other that boils at 160 degrees to 180 degrees 0., mixtures are obtained which contain various solid nitrocompounds with oily ones, and by the use of these, explosives exhibiting other properties can be produced, as, for exam le, those that are obtained when either y those solid nitro-compounds resulting from the first or third fraction are employed; or only those oily ones resulting from the second fraction; or again, mixtures of the three sorts of the same which are obtained when the solvent naphtha is nitrated as it is. But the known methods of nitration of the aromatic hydrocarbons are not suitable for the nitration of solvent naphtha. These, and also their separate fractions, are a mixture of various hydrocarbons which behave in various ways when treated with a mixture of nitric and sulfuric acids. If therefore the solvent naphtha, or its separate fractions, is or are nitrated in the usual way, the hydrocarbons.

contained in the solvent naphtha are partly destroyed by oxidation and partly sulfonated so that finally, instead of the nitrocompounds, mixtures of them with nitroand sulfo-compounds are obtained that are diificult to se arate, and the only useful nitro-compoun s therein are not in a ure condition, and can only be isolated and prolonged operations with a very sma 'eld. It is therefore necessary to proceed 1n the following Way and without regard to whether the solvent naphtha is submitted to nitration as it is or in separate fractions.

The nitrating acid'consists of 65 parts by volume of nitric acid of 1.49 to 1.52 specific gravity, and 13.5 arts by volume of sulfuric acid of 1.84 speci c gravity. Into 60 liters f such nitrating acid are allowed to run hters of solvent naphtha, or of one of its above mentioned fractions, while being vi orously agitated and cooled at 25 degrees .liters of nitrating acid are now added during vigorous agitation, then the mixture is slowly heated to 80 degrees centigrade and then while agitated, cooled to 25 degrees C. The acid is then removed and the only products formed is again nitrated by the addition of 60 liters of fresh acid mixture as above specified and 45 litres of sulfuric acid of 1.84 specificgravity, while the temperature is againallowed to rise to 80 degrees centigrade and then cooled as before to 25 degrees C. and finally the acid is drawn off. This latter can afterwards be used in a fresh operation as preliminary nitration acid, that is to say, for the first nitration. The product freed from the acid, is, according to whether the whole solvent naphtha or a separate fraction thereof has been nitrated,

either half solid, solid, or oily. It is then nitrating the naphtha by mixingit with the described mixture of nitric and sulfuric acids; and then simultaneously cooling and agitating the same; then separating the mixed acids from the partiall nitrated naphtha; com leting the nitration of the latter with a resh acid mixture containing a greater relative proportion of sulfuric acid than the first mixture, and cooling as before, and finally removing the mixed acids from the nitrated naphtha and washing the latter with water substantially as described.

2. The process of producing a mixture of 1 aromatic nitro-compounds from purified solvent naphtha as hereinbefore specified hav' ing a boiling point of 120 degrees to 180 degrees 0., consisting in preliminarily nitrat-v ing the naphtha by ag tating it with the described mixture of nitric and sulfuric acids, slowly heating the mixture, simultaneously cooling and agitating the same, separating the mixed acids from thepartially nitrated naphtha, completing the nitratlon of the latter with a fresh acid mixture as described containing a greater relative proortion of sulfuric acid than the first, while eating and cooling as before, removing the mixed acids from the nitrated naphtha and washing the latter with water substantially as described.

3. The process of producing a mixture of aromatic nitro-compounds from pur fied solvent naphtha as hereinbefore spec fied having a boiling point of 120 degrees to 180 degrees 0., consisting in preliminarllynitrating the naphtha by agitating it with the described mixture of nitric and sulfuric acids while cooling the mixture, then heating residual acids and Washing the nitro-comand afterward cooling the mixture, separatpounds with water. ing the residual'mixed acids from the par- In testimony whereof I have signed my tially nitrated naphtha, completing the name to this specification in the presence of 5 nitration of the laigtler Withda fresh mlxture two subscribing witnesses.

o nitric and su ric aci s containing a greater relative proportion of sulfuric acid GUSTAV S than the first while heating and cooling as Witnesses: before, separating the resulting mixture of MAURICE LILIENFELD, 10 solid and liquid nitro-compounds from the EMIL PAPENBRUOH. 

